The present invention relates to a film deposition technique which is applicable to the single-layer or multi-layer formation of thin-films of various elements or compositions on substrates of metals, semiconductors or insulators.
Pursuant to conventional prior art physical vapor deposition, a crucible having an opened end is provided within a high vacuum region or low gas pressure region. A material to be vaporized is supplied into and heated within the crucible and the generated vapor of the material is deposited onto a substrate.
Nevertheless, during the heating of the crucible, the vapor pressure corresponding to the particular heating temperature diffuses through the opened end of the crucible at one time such that the degree of vacuum of the substrate containing region declines due to the vapor of the material within the crucible. In addition, many other difficulties are encountered, for example, blackening of deposited films and roughing of particles of the deposited films. Due to the boiling phenomenon occurring within the crucible, splashed material will disperse outside the crucible and will result in attachment onto the surface of the deposited films. Therefore, restrictions are placed on the heating temperature of the crucible depending upon the physical properties of the material received within the crucible.
Meantime, even when the crucible is heated to high temperatures while experiencing the difficulties mentioned above, the resulting thermal energy is extremely small from the viewpoint of the kinetic energy. That is to say, as will be clear from the formula KT/e=T/1.16.times.10.sup.4, conversion of the thermal energy corresponding to T(.degree.K.) into the kinetic energy shows that, for example, when heating the crucible up to 2300.degree. K. the kinetic energy is only 0.2 eV. The merits due to the kinetic energy, therefore, are hardly expected by the conventional vacuum deposition technique.